Lets say that the European colonial powers stay strong or not weaken greatly. Maybe the world wars are just avoided somehow. Could they have gradually adopted a less racist out look on foreign holds within their empires. Let's say they take a more Roman or Latinization outlook on colonies. They could even use Roman as example and justification for this. As the 1900s progresses in this world racial supremacy beliefs become less favored and supported like our world but are replaced by a belief in cultural supremacy. I remember reading one book a while go that quoted statements from the mid 1800s about how the British were better because of their culture more so then race. It basically said the British were uncivilized savages before Rome and Christianity civilized them. It stated the British must bring "civilization" to the "uncivilized" and "uplift" them like the Romans did for Europeans. What if this belief becomes the trend? Basically if a African or Asian acts "British", "French", or whatever European culture rules them they should be treated as such. Maybe instead of decolonization in some places we see integration into European society. Maybe Africa experiences a civil rights movement that calls for equality within the empire. I see this working the best for France considering their more open belief about nationality and the French identity. Italy could maybe also be more open to it. Just to be clear the empires still don't have to be nice about it. They could choose to enforce it through various measures. This could include a mix of economic, political, and social gains for people in the colonies who choose to adopt the colonizer culture. It could be done by authoritative and oppressive measures. It could also be done by a mix of the previous ones. Reward natives greatly for assimilating while oppressing or even breaking down on the unwilling. Additionally, these measure could vary between colonies. They could be encouraged it in some colonies while not in others. I see more established cultures being harder to force assimilation on. For example, many Muslims and Asians would probably be much harder to convince or force to accept assimilation into European culture then non-Islamic Africans. I feel like non-Islamic Africans do share a lot in common with much of pre-Roman Europe especially regarding society structure and cultural development. In our world the missionaries were successful in making Africans convert to Christianity which is probably the first step to assimilation. Second could European powers destroy most native languages in many areas and make European ones the sole language spoken by the people or at least among most of them? For example Nigerians would only speak English and people in Congo only speak French or Dutch. There would not be 50 languages spoken in one country. The languages can have regional dialects but still the same language as the European rulers. I could see many unwritten or smaller in number languages being wiped out. A common language makes assimilation easier. After that could Europeans make some people in the colonies no matter race look at themselves as the same people or at least connected with the colonizers?